/* -*-c++-*- */
/* osgEarth - Geospatial SDK for OpenSceneGraph
 * Copyright 2020 Pelican Mapping
 * http://osgearth.org
 *
 * osgEarth is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>
 */
#ifndef OSGEARTH_UTIL_LINE_OF_SIGHT_H
#define OSGEARTH_UTIL_LINE_OF_SIGHT_H

#include <osgEarth/Common>
#include <osg/Group>

namespace osgEarth { namespace Contrib
{
    using namespace osgEarth;

    struct LineOfSight
    {
        /**
         * The line of sight display mode
         */
        enum DisplayMode
        {
            /**
             * Split mode draws a line in the good color from the start of the line to the first hit, then a bad line from the hit to the end
             */
            MODE_SPLIT,
            /**
             * Single mode draws a single line from start to end and colors it good or bad depending on whether there is line of sight or not.
             */
            MODE_SINGLE
        };
    };


    /**
     * Base class for LOS node implementations
     */
    class /* no export */ LineOfSightNode : public osg::Group
    {
    public:
        LineOfSightNode() { }
        virtual ~LineOfSightNode() { }
    };


    /** 
     * Callback for LOS change notifications 
     */
    struct LOSChangedCallback : public osg::Referenced
    {
    public:
        virtual void onChanged() {};

        /** dtor */
        virtual ~LOSChangedCallback() { }
    };

    typedef std::list< osg::ref_ptr<LOSChangedCallback> > LOSChangedCallbackList;


} } // namespace osgEarth::Util

#endif // OSGEARTH_UTIL_LINE_OF_SIGHT_H
